Day 1: NY Fashion Week

Blake Lively

The Gossip Girl joined a bevy of beauties, including Camilla Belle and Bar Refaeli, at the Ralph Lauren store for Fashion's Night Out festivities. Lively wore a rustic ensemble from Ralph Lauren Collection.

-with reporting by Joyann King, Christina Shanahan and Betony Toht

Ben Hollingsworth and Chace Crawford

The Beautiful Life

met Gossip Girl as actors Ben Hollingsworth and Chace Crawford crossed paths at the D&G boutique in honor of Fashion's Night Out. The small-screen heartthrobs (who were each decked out in D&G) enjoyed a performance of up-and-coming Brooklyn band, Asa Ransom, alongside stars like Molly Sims and Kristin Cavallari.

Rihanna

At the Intermix event for Fashion's Night Out, Rihanna wore her (studded) sunglasses at night, along with a cowl-neck minidress and leather gloves. The songstress took in a live art competition by ART BATTLES, as well as a set by downtown favorites, DJ Harley Viera Newton and Cassie Coane.

Savannah and Sienna Miller

Twenty8Twelve designers Savannah and Sienna Miller took a break from styling their upcoming spring collection to host a gathering at Soho's Intermix. Sienna is currently starring in Broadway's After Miss Julie, necessitating transatlantic participation in the London-based line. "She literally gets offstage, gets on a plane, goes on the runway, gets back on the plane and then gets back on the stage," said Savannah. "Insane!"

Ashley and Mary-Kate Olsen

Cheers! Designers Ashley and Mary-Kate Olsen took to the cocktail shakers at Bergdorf Goodman as part of Fashion's Night Out. The sisters later handed out libations at the Barneys launch of their The Row men's line.

Giuseppe Zanotti and Victoria Beckham

Bergdorf Goodman hosted pals Giuseppe Zanotti and Victoria Beckham for a Fashion's Night Out appearance. Posh made her mark, signing T-shirts for eager fans, but skipped a low-key ensemble in favor of a Giles corset dress and over-the-knee Gucci boots.

Michelle Trachtenberg and Katy Perry

Michelle Trachtenberg and Katy Perry stood tall in appreciation of stiletto guru Giuseppe Zanotti at his N.Y.C. boutique. The duo celebrated the shoe master alongside Rachel Bilson, Rihanna and Taylor Momsen.

Kate Hudson

After joining a host of celebrities for the Fashion's Night Out kickoff party, Kate Hudson slipped into a Stella McCartney jumpsuit for a T-shirt signing at the designer's Manhattan boutique.

Gwen Stefani

The No Doubt frontwoman proudly debuted her latest collection at Milk Studios. "It's kind of a rebirth of L.A.M.B." Gwen Stefani said of her spring line. "There are a lot of jersey and asymmetrical pieces and I kept it really simple color-wise with a lot of black, white, gray and pops of color." The rocker, who says she won't get the chance to view any other designers' collections, later joined the Fashion's Night Out festivities at Bloomingdales. "I've been in tour-mode, so to be dropped back in New York into Fashion Week feels like a Saturday Night Live skit...it's so hilarious and over the top," she said. "I love how fun it is and I can't believe I get to keep doing it."

Charlize Theron

Statuesque beauty Charlize Theron visited the Dior boutique in honor of Fashion's Night Out. The actress greeted fans wearing a silver satin dress courtesy of the design house.

Michael Kors and Debra Messing

The sweet smell of success! Debra Messing joined Michael Kors for the Macy's Herald Square launch of the designer's latest fragrance, Very Hollywood. The actress walked an appropriately red carpet in a single-shoulder dress by the Project Runway judge.

Sarah Jessica Parker, Barbara Walters and Bette Midler

One night only! Sarah Jessica Parker, Barbara Walters and Bette Midler raised their voices in song along with Oscar de la Renta in a performance of "As Time Goes By." The show took place in the designer's boutique as part of Fashion's Night Out.

Tiffani Thiessen

Tiffany Thiessen

booked it straight from the set of her new show, White Collar, to the Bryant Park tents just in time to see Tia Cibani's Japanese and nature-inspired designs for Ports 1961. "It was actually easy which was kind of nice," said Thiessen, who went for simple chic in a black Ports 1961 dress and Elizabeth and James shoes. Ivanka Trump and Law and Order SVU's Stephanie March also joined the actress in the front row.

JoAnna Garcia

"I love BCBG," announced Privileged lead JoAnna Garcia, following the Bryant Park show. "I go home and I am like, 'Here's my money-I want to buy it all!'" The BCBG-clad star then gave us the scoop on her priceless new role. "I was amazed at how much I made out this summer on Gossip Girl," Garcia dished. "My character's plot with Chace Crawford is a nice little Romeo and Juliet love story with a little twist at the end."